Ozone treatment method for treating a substance to be treated by ozone oxidation, the method comprising a step of supplying ozone into water to be treated that comprises a substance to be treated, in the presence of the ozone oxidation accelerator, wherein :- the ozone is supplied by bubbling and- the ozone oxidation accelerator is at least one compound selected from the group consisting oforganic acids having 7 to 10 carbon atoms and salts thereofalcohols selected from the group consisting of pentanediol, 2-methyl-2,4-pentanediol,diacetone alcohol, 3-methyl-1,3-butanediol, 2-methyl-1,3-butanediol, 3-methyl-1,4-butanediol, 2-methyl-1,4-butanediol, 2-methyl-1,2 butanediol, and 3-methyl-1,2-butanediolether selected from the group consisting of diethyleneglycol monoalkylether, diethyleneglycol dialkylether. propyleneglycol monoalkylether, propyleneglycol dialkylether, dipropyleneglycol monoalkylether, and dipropyleneglycol dialkylether and ester compound represented by the following general formula (I)x is 0 to 4 and R1, R2, and R3 independently represents a group selected from the group consisting of -H, -OH, a group represented by the following general formula (1), and a group represented by the following general formula (2), while at least one of R1, R2, and R3 is a group represented by the following general formula (2):R4 is an alkyl group having 1 to 4 carbon atoms.
